The present invention relates to a hydraulic control valve formed as a magnet valve with several connections and several switching positions.
In particular, it relates to a hydraulic control valve of the above mentioned type, which has a housing provided with the connections and an electromagnet with displaceable plunger for controlling a valve slider, and which is provided with a valve seat and a ball movable by a closing spring in a closing position and also movable in an opening position by the control slider under the action of the electromagnet.
Such control valves are used conventionally for controlling hydraulic cylinder-piston units, for example for lifting and lowering aggregates of agricultural harvesting machines. These valves are known as multi-way valves with several switching positions. The above described valves which are generally satisfactory have however the disadvantage that the beginning of a lifting or lowering step as well as the end is performed in a strike-like manner. The thusly produced accelerating or braking forces are extremely high so that they cause correspondingly nigh loads of their components. Thereby vibration and shaking movements are produced, which are always undesirable.
Moreover, in the known control valve there is another disadvantage that the repair works are expensive. During a repair, the complete control valve must be changed. Because of these requirements it must always be guaranteed that the valve is leakage-free.